2-甲基丙烯酸羥基乙酯表面接枝於聚甲基丙烯酸甲酯其抗菌貼附之機制研究暨臨床試驗

Abstract

聚甲基丙烯酸甲酯主要應用於牙科矯正維持器及假牙基底樹酯，因口內微生物環境複雜，易使微生物貼附於聚甲基丙烯酸甲酯形成生物膜，造成齲齒及牙周病，故其表面的改質為學者們所致力的目標。我們發現將2-甲基丙烯酸羥基乙酯以熱處理方式接枝於聚甲基丙烯酸甲酯可抗細菌貼附且具生物相容性，但其抗貼附機制和真正應用於人類口腔內是否有效仍不明確。 本論文我們將藉由薄膜界面電位分析儀和胞外多醣體酚-硫酸法探討聚甲基丙烯酸甲酯(PMMA)以及表面接枝2-甲基丙烯酸羥基乙酯之聚甲基丙烯酸甲酯(PMMA-HEMA)表面電位影響細菌貼附情形以及細菌貼附於表面上所必需分泌的胞外多醣體多寡，並且也將PMMA和PMMA-HEMA進行臨床試驗，藉由共軛焦顯微鏡和電子顯微鏡去觀察口腔內細菌貼附於試片表面上的情況以及活菌和死菌的比例。 結果顯示PMMA-HEMA的表面電位比PMMA較為帶負電，且因細菌的胞外膜為負電，能使其表面與細菌外膜有相斥的作用。此外經過細菌培養後萃取PMMA-HEMA表面細菌所分泌的胞外多醣體，測得的量也微乎其微。顯示其表面可抗細菌貼附而無胞外多醣體沾黏於表面上，所以細菌無法彼此聚集形成生物膜。臨床試驗中也發現PMMA-HEMA表面的細菌貼附量比PMMA少，故使用熱處理接枝HEMA於PMMA表面上應用於人體口腔內仍有抗細菌貼附的效果。

Polymethyl methacrylate (PMMA) is mainly used in orthodontic removable retainer and denture base resin. Because intraoral microorganism environment is complex, microorganisms easily attach to PMMA and form biofilm. Uncontrolled accumulation of bacteria and fungal biofilms on or surrounding dental devices may contribute to dental caries and periodontal disease. Surface modification on polymeric materials and control of microbial infections are a very important issue in modern society. We found that 2-hydroxyethyl methacrylate (HEMA) grafted onto heat-treated PMMA could decrease bacteria adhesion and possess biocompatibility. However, it is still unclear about PMMA-HEMA’s antiadhesion mechanism and application in human oral cavity. In this study, the zeta potential of PMMA and PMMA-HEMA surfaces and extracellular polysaccharides produced by bacteria were evaluated by electro-kinetic analyzer (EKA) and phenol-sulfuric acid method. Furthermore, the PMMA and PMMA-HEMA antibacterial adhesion clinical trial was observed by confocal laser scanning microscope and scanning electron microscopy. We analyzed the circumstances of oral bacterial attachment as well as the proportion of live bacteria and dead bacteria. Results of the PMMA and PMMA-HEMA surface zeta potential showed that PMMA-HEMA carried more negative charge compared to PMMA. Therefore, PMMA-HEMA exhibited ability to repel bacterium which had negative charge on cell wall. Moreover, we measured scanty extracellular polysaccharides on PMMA-HEMA surface which demonstrated that PMMA-HEMA inhibited biofilm formatin by antiadhesion of bacterial extracellular polysaccharides. In clinical trial, PMMA-HEMA prevented the adhesion of oral bacterium than PMMA. Therefore, the heat-treated PMMA-HEMA has antibiofilm activity and exhibits a potent broad spectrum antibacterial activity against salivary bacteria.